PROJECT SUMMARY Tissues which live within joints, including the anterior cruciate ligament, rotator cuff tendon, meniscus and labrum fail to heal spontaneously after injury and have high failure rates of surgical repair. The ACL represents a good model to study the problem of intra-articular healing as there are validated preclinical models and clinical outcome measures that make it possible to critically evaluate the success or failure of strategies to enhance tissue healing. The current standard of care for ACL injuries is ACL reconstruction, which is good at stabilizing the knee but requires compromising other uninjured structures around the knee to obtain a graft that is subsequently used to replace the ACL. Further the early posttraumatic OA is not mitigated despite ACL reconstruction. The preclinical studies on ACL repair called BEAR (Bridge-Enhanced ACL Repair) demonstrated a prevention of posttraumatic OA and achieved knee stability. The positive preclinical findings of BEAR compared to ACL reconstruction provided the foundation for two FDA approved preliminary clinical trials: 1) the first-in-human cohort study (?BEAR I?), and 2) a small, single-center randomized control trial (?BEAR II?). The statistical analysis of our pilot data shows a 200 patient trial will be required to demonstrate non-inferiority of BEAR (a novel paradigm changing technology) when compared to ACL reconstruction (current gold standard) for the key outcomes of anterior-posterior (AP) knee laxity and a validated patient reported outcome for knee surgery. Therefore we propose the BEAR-MOON (Bridge-Enhanced ACL Repair) multi-center randomized non-inferiority clinical trial for co-primary outcomes AP (anterior-posterior) knee laxity and International Knee Documentation Committee (IKDC) validated patient reported outcome measure. The subjects will be between 18 and 40 years of age with a complete ACL tear and randomized to either 1) ACL Reconstruction with patellar tendon autograft (ACLR) or 2) Bridge-Enhanced ACL Repair (BEAR). We will follow subjects at 6 months, 1 and 2 years after surgery. While achieving these aims has the potential to change the clinical practice of ACL surgery, the impact is potentially far greater, as the availability of an FDA- approved carrier that can be used to deliver complex biologic therapies to tissues within joints could enable the clinical translation of the preclinical studies being conducted in multiple areas of regenerative medicine by providing a delivery vehicle for these therapies.